Understanding and choosing a Medicare Part D prescription plan can seem like a daunting task. With bureaucratic names like Part A, B, and D, and complicated lists and formularies (charts that outline insurance coverage), it's easy to get overwhelmed. But if you take the time to get familiar with Medicare, how it works, and what it covers, you'll be better prepared for choosing the right prescription plan for your needs.

The following is an introductory guide to choosing Part D plans, including information about eligibility requirements, medication coverage, and more.

Eligibility for Medicare Part D Prescription Plans

If you're eligible for Medicare Part A or Part B, then you're eligible for Medicare Part D. You do not have to be screened to be eligible, and joining Part D is completely voluntary. However, if you're eligible and don't join -- but wish to do so at a later date -- you'll pay a penalty. Note that usage of some parts of Medicare precludes usage of other parts, so explore all parts of Medicare before deciding which parts will best suit you.

General eligibility for Medicare begins when you're 65, but you can join three months before or after your 65th birthday. You can determine your eligibility and find out when coverage would start by visiting Medicare's website.

Current Medications and Current Coverage

If the drugs you take now are currently covered under your existing plan, or you don't take any prescription drugs, you should still consider a Medicare Part D prescription plan. In many cases Medicare will let you keep your existing prescription drug plan, or will offer you alternatives. As previously mentioned, if you decide to enroll at a later date, you may be penalized, so it pays to explore your eligibility for Part D even if you're currently covered or don't have any need.

Yearly Deductibles - You'll pay a yearly deductible, if any is due, unless you qualify for extra assistance.

Co-Payments - You'll owe a co-payment or co-insurance for each prescription, unless you qualify for extra assistance.

As noted, each of these payments can be offset if you qualify for extra assistance, visit the Medicare website to see if you are eligible for additional compensation.

The general goal when choosing a plan is to look for the plan that provides the overall lowest cost per year. To calculate the cost per year, you can approximate it by simply adding up your premiums, deductibles and co-payments for your drugs. Finally, add in the costs associated for purchasing drugs during any gap in coverage (see gap coverage below).

Gap Coverage

The first thing to understand when considering Part D is what is known as the "coverage gap." While the amounts change regularly to keep up with inflation and rising drug costs, the coverage gap begins once you've accrued $3,750 in covered drug costs (as of 2018). Once you've reached this limit, you'll pay no more than 35 percent of the plan's cost for brand-name medications (as long as they're covered). Medicare pays 56 percent of the cost of generic drugs (as of 2018).

Once you pass $5,000 in out-of-pocket expenses (2018) -- meaning you're out of the coverage gap -- you move into what is known as "catastrophic coverage." Medicare will cover you again, typically resulting in you paying a nominal coinsurance amount or copayment for covered medications.

This coverage gap doesn't apply to low-income Medicare recipients.

What Your Part D Drug Plan Covers

Each Part D plan will have a list of different drugs that it covers in the plan's formulary. The formulary will let you know the name of the drug it covers (generic and brand-name), how much you would co-pay, and what limitations there are on that drug's coverage.

If the drug you need isn't on the list, you'll have to pay full price for that medication or use a similar drug that the plan covers. You can also apply to the plan for an exception to its coverage, but don't rely on this working out, it's better to start with a program that covers your existing medication.

Prescription Drug Plans (PDPs) - PDPs are stand-alone programs, that focus on and cover prescription drugs only, as opposed to health care needs generally. People who already have general Medicare (Part A or B) and people who have a Medicare Private Fee-For-Service (PFFS) plan typically choose PDPs.

Advantage Plans with Prescription Coverage (MA-PDs) - MA-PDs are general health care plans that also cover prescription drugs and come in 4 flavors, HMOs, PPOs, PFFS and Special Needs Plans (which are only for very specific groups of people). These are managed care programs that will lock you in to certain hospitals and doctors, but generally cost less money.

Which type of plan you choose will largely be based on the amount of money you can spend and the type of coverage you need.

Pick a Plan

Picking a plan can seem like a monumental task, but it really boils down to the basics. You should choose a plan based on:

How much the plan costs;

What drugs the plan covers;

Your existing health;

Your existing insurance coverage; and

Whether you have specific hospitals, doctors or pharmacies you wish to use.

Trying to Choose a Medicare Part D Prescription Plan? An Attorney Can Help

When choosing prescription coverage through Medicare, you'll want to take stock of your particular needs and means, such as monthly income and health conditions. But each situation is different and you may need help determining how the laws and regulations pertain to you. Reach out to a local, experienced health care law attorney today.